US3954431A - Optical glass and its production - Google Patents

Optical glass and its production Download PDF

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US3954431A
US3954431A US05/509,652 US50965274A US3954431A US 3954431 A US3954431 A US 3954431A US 50965274 A US50965274 A US 50965274A US 3954431 A US3954431 A US 3954431A
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mole percent
glass
produced
constituent
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James William Fleming, Jr.
Raymond Edward Jaeger
Thomas John Miller
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AT&T Corp
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Bell Telephone Laboratories Inc
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    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00Glass compositions
    • C03C3/04Glass compositions containing silica
    • C03C3/076Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B19/00Other methods of shaping glass
    • C03B19/01Other methods of shaping glass by progressive fusion or sintering of powdered glass onto a shaping substrate, i.e. accretion, e.g. plasma oxidation deposition
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01Manufacture of glass fibres or filaments
    • C03B37/012Manufacture of preforms for drawing fibres or filaments
    • C03B37/0128Manufacture of preforms for drawing fibres or filaments starting from pulverulent glass
    • C03B37/01291Manufacture of preforms for drawing fibres or filaments starting from pulverulent glass by progressive melting, e.g. melting glass powder during delivery to and adhering the so-formed melt to a target or preform, e.g. the Plasma Oxidation Deposition [POD] process
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C1/00Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels
    • C03C1/02Pretreated ingredients
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C13/00Fibre or filament compositions
    • C03C13/04Fibre optics, e.g. core and clad fibre compositions
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00Glass compositions
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00Glass compositions
    • C03C3/04Glass compositions containing silica
    • C03C3/06Glass compositions containing silica with more than 90% silica by weight, e.g. quartz
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00Type of glass produced
    • C03B2201/06Doped silica-based glasses
    • C03B2201/08Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant
    • C03B2201/10Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant doped with boron
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00Type of glass produced
    • C03B2201/06Doped silica-based glasses
    • C03B2201/30Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
    • C03B2201/31Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with germanium
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2201/00Glass compositions
    • C03C2201/06Doped silica-based glasses
    • C03C2201/08Doped silica-based glasses containing boron or halide
    • C03C2201/10Doped silica-based glasses containing boron or halide containing boron
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2201/00Glass compositions
    • C03C2201/06Doped silica-based glasses
    • C03C2201/30Doped silica-based glasses containing metals
    • C03C2201/31Doped silica-based glasses containing metals containing germanium
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2203/00Production processes
    • C03C2203/10Melting processes

Definitions

  • the invention relates to the production of high quality optical glasses suitable for incorporation in devices such as lenses and optical transmission lines.
  • a method for the production of mixed oxide glasses which include components which differ significantly in volatility at required glass melting temperatures.
  • This method has been found to be adaptable to the production of glasses of high optical quality such as are useful for the production of optical waveguides.
  • the processing steps of this method are compatible with the maintenance of high degrees of purity, uniformity and good composition control.
  • the method consists essentially of the use of a plasma to fuse prereacted powders into a solid mass of optical glass.
  • Exemplary experimental work has been done in the SiO 2 --GeO 2 --B 2 O 3 system.
  • Glass compositions have been developed for the core and cladding materials of optical waveguides which are sufficiently different in index of refraction to provide guidance yet sufficiently similar in coefficient of expansion to provide low levels of internal stress.
  • FIG. 1 is a ternary compositional diagram of exemplary glass compositions showing the approximate location of exemplary lines of constant index of refraction and constant coefficient of expansion;
  • FIG. 2 is an elevational view in section of an exemplary portion of an optical waveguide
  • FIG. 3 is an elevational view in section, partially schematic, of an exemplary plasma fusion apparatus.
  • SiO 2 High purity fused silica, SiO 2 , has been shown to possess very little attenuation for electromagnetic radiation in the visible and near visible region of the spectrum. Thus, it has found use in optical devices and has been extensively investigated in connection with optical transmission for communications. Because of a desire to make devices incorporating glasses of different indexes of refraction, silica based glasses containing other oxides have been made. The glasses discussed here contain other oxides classified as "network formers" because they posses intermolecular bonding similar to SiO 2 .
  • Such oxides include B 2 O 3 , GeO 2 , SnO 2 , V 2 O 5 and Sb 2 O 3 .Although such oxides melt or sublime at much lower temperatures than SiO 2 the inclusion of minor quantities (a total of less than 50 mole percent) of such oxides in a silica glass does not greatly reduce the temperature to which such glasses must be raised in order to be homogenized and fined. This presents a composition control problem and makes it difficult to incorporate them to more than 5 mole percent without inordinately high loss. This is obtained because these oxides all possess at least 1.5 times, and in most cases at least ten times, the vapor pressure of SiO 2 at the required processing temperatures.
  • FIG. 1 is a ternary compositional diagram representing glasses containing different proportions of SiO 2 , GeO 2 B 2 O 3 .
  • This diagram shows exemplary lines of constant index of refraction at 0.589 ⁇ 11 (solid lines) and exemplary lines of constant coefficient of thermal expansion 12 (dashed lines) for annealed glasses in this system.
  • glasses in this system can be used for optical transmission lines (optical waveguides) such as shown in FIG. 2.
  • Such transmission lines incorporate a higher index of refraction glass core 21 and a lower index of refraction glass cladding 22.
  • the index difference required to obtain adequate guidance at any wavelength depends on the dimensions of the device and is commonly expressed in terms of the numerical aperture of the device. However, it is difficult to achieve guidance if the index difference is less than one half percent. Thus, the inclusion of at least approximately 8 mole percent GeO 2 in a germanosilicate glass is needed if the other glass is a borosilicate glass.
  • glasses possessing coefficients of expansion which differ by less than 20 percent in order to achieve low residual stress in the fabricated device.
  • the use of glasses which differ in coefficient of expansion by less than 5 percent is preferable in this respect.
  • germanosilicate glasses When made by the plasma fusion process discussed below it was found that the germanosilicate glasses possessed significantly fewer bubbles (essentially none in most cases) than the borosilicate glasses. It was particularly surprising that the inclusion of as little as 0.1 mole percent of GeO 2 in a borosilicate glass produced a significant reduction in bubble formation. Thus, the inclusion of from 0.1 to 5 mole percent GeO 2 in an otherwise pure borosilicate glass is recommended for bubble content reduction while holding the variation of refraction to within 10 percent of the total variation over the contemplated borogermanosilicate composition range.
  • Powders suitable for use in the production, by plasma fusion, of the above-described optical glasses have been produced by several methods. The following methods have proven most suitable when used in conjunction with the investigated glass system. However, other equivalent methods may find use in the production of other compositions.
  • a quantity of finely divided silica powder (for example, a powder with average partical size approximately 75 Angstroms) is combined with a solution containing constituents which, when in oxide form, constitute the other glass-forming materials.
  • a solution containing constituents which, when in oxide form, constitute the other glass-forming materials.
  • an aqueous solution of ammonium pentaborate ((NH 4 ) 2 B 10 O 16 .sup.. 8H 2 O) can be used when the production of a borosilicate glass is contemplated.
  • the slurry is liquid dried by spraying into a quantity of flowing ammoniated acetone.
  • the slurry is filtered and the filtered particles dried to produce the precursor material, which will subsequently be processed into the
  • all of the glass-forming materials are incorporated in solution and the mixed solution hydrolyzed by spraying into a quantity of ammoniated water.
  • tetramethoxy silane, Si(OCH 3 ) 4 , trimethoxy borine, B(OCH 3 ) 3 , and tetraethoxy germanium, Ge(OC 2 H 5 ) 4 can be used when the production of borogermanosilicate glass is contemplated.
  • Any one of a number of other organometallic or inorganic compounds may be used in this procedure (e.g., tetraethoxy silane, silicon tetrachloride, germanium tetrachloride and boric acid).
  • the damp powders produced by the filtering of the above produced slurries can be dried, for example, by placing them in an oven to bake in air or vacuum or other appropriate atmosphere at some elevated temperature. Exemplary powders have been dried in air or vacuum at approximately 110° C for times of more than 16 hours. This drying step produces a friable cake which can be gently crushed and screened to the desired particle size. Screening through a 20 mesh nylon screen has proved advantageous.
  • the particle matter thus produced is the precursor material for subsequent processing to the desired glassy powder.
  • the most desirable product for use in the ultimate plasma torch production of a glass boule would be bubble free, compositionally uniform and uniformly sized particles of the desired glass composition. It is the goal of the hereunder described powder preparation steps to approach as near as possible to this ideal.
  • the basic requirement is a heat treatment which reduces the compounds used, to oxide form and combines the oxides to produce a glassy or at least partially glassy material.
  • a two-step heat treatment has been found to be advantageous in this regard. The first step, some 200° to 400° centrigrade below the temperature of the subsequent step, serves to promote oxide formation and drive off volatile constituents leaving the glass forming materials primarily in oxide form.
  • the second step serves to combine the oxides to particles as near as possible to the ideal described above.
  • the second step heat treatment temperature is chosen to be as high as possible to maximize glass formation and compositional uniformity but not high enouth to produce an inordinate amount of agglomeration of the particles. This latter consideration is particularly important when the highest degrees of production purity are required. If the heat treatment temperature is not too high, the product remains particulate or forms a light friable cake which is easily crushed without vigorous grinding or other pulverizing steps which would provide an avenue for the introduction of impurities.
  • FIG. 3 shows an exemplary apparatus for the production of a boule of optical glass by the fusion of a powder in a plasma flame.
  • a high-powered r-f generator 31 (of the order of 10 100 kilowatts) excites the coil 32 of a plasma torch 33.
  • the plasma torch consists of a fused silica mantle 34 connected by a tube 35 to a source of gas 36.
  • the gas source 36 feeds the gas desired for the plasma discharge 37 into the mantle 34.
  • the plasma discharge 37 produces an incadescent flame whose temperature can reach of the order of 20,000° C at its center.
  • Plasma torches are described in the literature (e.g., International Science and Technology, June 1962, page 42).
  • the powders to be fused are directed into the flame 37 by a tube 38 from a powder source 39.
  • the powder source 39 consisted of a vibratory powder feeder which continuously introduced a regulated quantity of powder into a stream of helium gas flowing at a rate of approximately 140 liters per hour. The power feed rate was adjusted somewhat after visual observation of the forming boule, starting at a rate of 200 grams per hour.
  • the powder-gas stream from the powder source 39 is directed against the center of the molten portion 43 of the forming boule 40.
  • Boule formation is initiated by directing the powder-gas stream against a bait 41.
  • the bait 41 is supported on a pedestal 42, which is rotated in order to promote the symmetry of the boule 40.
  • the pedestal is lowered at a rate sufficient to keep the position of the molten 43 portion of the boule 40 constant relative to the flame 37 and feed tube 38.
  • a powder containing 84.5 mole percent SiO 2 and 15.5 mole percent B 2 O 3 was produced by stirring together 3.2 liters of triply distilled water, 186.7 grams of (NH 4 ) 2 B 10 O 16 .sup.. 8H 2 O and 309 grams of an amorphous silica powder having an average particle size of less than 100 A.
  • the mixture was stirred for 2 hours at 60° C to produce a slurry.
  • the slurry was sprayed into a stirred bath approximately 10 times its volume of a 25-to-1 by volume mixture of acetone and NH 4 OH solution.
  • the NH 4 OH solution was 28 weight percent NH 4 OH in water.
  • the resulting particles were filtered from the solution and dried at 110° C for at least 16 hours. The drying time and temperature are not critical.
  • the dried powder formed a friable cake, which was placed in a plastic bag and crushed.
  • the resulting powder was passed through a 20 mesh nylon screen.
  • the screened powders were placed in a fused silica dish and raising the temperature of the powder from room temperature at a rate of 200° centigrade per hour in a furnace while the powder was exposed to air and heat treated at 600° C for 2 hours then at 750° C for 2 hours, cooled to 500° C in the furnace and removed to room temperature.
  • the heat treated powder was a friable cake which was crushed gently in a plastic bag and screened through a 20 mesh nylon screen onto a 100 mesh nylon screen. The powder which did not pass through the 100 mesh screen was used to produce bulk glass by plasma fusion.
  • the powder was placed in a vibratory powder feeder, which fed the powder at a rate of approximately 200 grams per hour into a stream of helium gas flowing at approximately 140 liters per hour into a 3 mm inner diameter tube.
  • the gas-powder mixture was directed into the plasma flame against the fused surface of the forming boule through a fused silica injection probe withh a 3 mm inner diameter.
  • Boule growth was initiated by directing the powders at the surface of a fused silica bait consisting of a 3.8 cm diameter plate, 0.3 cm thick.
  • the bait and forming boule were rotated at 100 revolutions per minute and lowered at a rate sufficient to keep the molten surface of the forming boule at a constant position relative to the flame and the injection probe.
  • a boule of optical glass (containing few bubbles) approximately 5 cm in diameter and 5 cm long was produced.
  • the composition of the glass was 84.5 mole percent SiO 2 and 15.5 mole percent B 2 O 3 .
  • a powder containing 85.6 mole percent SiO 2 , 4.9 mole percent GeO 2 and 9.5 mole percent B 2 O 3 was produced by stirring together, at room temperature, 486 ml of tetramethoxysilane, Si(OCH 3 ) 4 , 89.7 ml of trimethoxy borine, B(OCH 3 ) 3 , and 44.2 ml of tetraethoxy germanium, Ge(OC 2 H 5 ) 4 .
  • the solution was injected through a 0.01 mm diameter orifice into a swirling bath of 10 times its volume of an ammoniated water solution.
  • the ammoniated water solution was made by mixing water and a 28 weight percent NH 3 OH aqueous solution in a 25:1 ratio by volume.
  • the resulting particles were filtered and dried at 110° C for at least 16 hours. The drying time and temperature are not critical.
  • the resulting material was processed to a powder between 20 mesh and 100 mesh size as in Example 1, except for the fact that the high temperature heat treatment took place for four hours at 925° C.
  • the resulting powder was fused into a boule of optical glass by a plasma fusion process essentially similar to Example 1.
  • the composition of the glass was 87.5 mole percent SiO 2 , 4.3 mole percent GeO 2 and 8.2 mole percent B 2 O 3 . This glass was essentially bubble free. Through the growth of several compositions it was determined that as little as 0.1 mole percent GeO 2 in a borosilicate glass was sufficient to greatly reduce or essentially eliminate bubble formation in these glasses.
  • the plasma flame was produced by a 35 kilowatt RF generator, exciting O 2 flowing at approximately 900 liters per hour in a 30 cm inner diameter plasma torch.

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Abstract

High silica content optical glasses, containing more volatile oxides such as GeO2 and B2 O3, are produced by plasma fusion of powders without inordinately high loss of the more volatile constituents. The powders are produced by a process including the heat treatment of intimately mixed materials, which include the glass forming constituents. Small quantities of GeO2 are included in borosilicate glass to suppress bubble formation. Pairs of glass compositions have been found, with sufficient index of refraction difference to produce guidance in optical transmission lines, while possessing sufficient thermal expansion match to reduce stresses in the line.

Description

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the production of high quality optical glasses suitable for incorporation in devices such as lenses and optical transmission lines.
2. Brief Description of the Prior Art
Flame fusion and plasma fusion have been used to form various crystalline and glassy materials using gaseous and particulate feed stocks together with reactive and inert carrier gases (Journal of Applied Physics, 32 (12) p.2534; Offlegungsschrift No. 2,239,249 Mar. 8, 1973 in German Patent Office). There has been a great deal of recent effort directed to the fabrication of glasses for use as waveguides in the optical and near optical region of the electromagnetic spectrum (Proceedings of the I.E.E.E., 61 (1973) p.452). Such optical waveguides are required to have a higher index of refraction region surrounded by a lower index of refraction region. The thrust of this work has been the provision of high index and low index glasses exhibiting little absorption or scattering loss at the wavelength desired for optical communication. Factors which effect these losses have been found to be the homogeneity, purity and composition of the glasses used.
Much investigation has been concentrated on fused silica and mixed oxide glasses with a high silica content (Materials Research Bulletin, 8 (1973) p.469). Many of the mixed glasses investigated, including some of the apparently desirable glasses, include oxides which are significantly more volatile than silica at glass fusion temperatures. This fact presents a problem of composition control during fabrication due to loss of the more volatile constituents.
SUMMARY OF THE INVENTION
A method has been found for the production of mixed oxide glasses which include components which differ significantly in volatility at required glass melting temperatures. This method has been found to be adaptable to the production of glasses of high optical quality such as are useful for the production of optical waveguides. The processing steps of this method are compatible with the maintenance of high degrees of purity, uniformity and good composition control. The method consists essentially of the use of a plasma to fuse prereacted powders into a solid mass of optical glass. Exemplary experimental work has been done in the SiO2 --GeO2 --B2 O3 system. Glass compositions have been developed for the core and cladding materials of optical waveguides which are sufficiently different in index of refraction to provide guidance yet sufficiently similar in coefficient of expansion to provide low levels of internal stress. In addition, it has been found that the inclusion of small amounts of GeO2 in predominantly borosilicate glasses suppresses the formation of bubbles in the glass mass during fusion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a ternary compositional diagram of exemplary glass compositions showing the approximate location of exemplary lines of constant index of refraction and constant coefficient of expansion;
FIG. 2 is an elevational view in section of an exemplary portion of an optical waveguide; and
FIG. 3 is an elevational view in section, partially schematic, of an exemplary plasma fusion apparatus.
DETAILED DESCRIPTION OF THE INVENTION Glass Compositions
High purity fused silica, SiO2, has been shown to possess very little attenuation for electromagnetic radiation in the visible and near visible region of the spectrum. Thus, it has found use in optical devices and has been extensively investigated in connection with optical transmission for communications. Because of a desire to make devices incorporating glasses of different indexes of refraction, silica based glasses containing other oxides have been made. The glasses discussed here contain other oxides classified as "network formers" because they posses intermolecular bonding similar to SiO2. Such oxides include B2 O3, GeO2, SnO2, V2 O5 and Sb2 O3 .Although such oxides melt or sublime at much lower temperatures than SiO2 the inclusion of minor quantities (a total of less than 50 mole percent) of such oxides in a silica glass does not greatly reduce the temperature to which such glasses must be raised in order to be homogenized and fined. This presents a composition control problem and makes it difficult to incorporate them to more than 5 mole percent without inordinately high loss. This is obtained because these oxides all possess at least 1.5 times, and in most cases at least ten times, the vapor pressure of SiO2 at the required processing temperatures.
Exemplary of the glasses investigated and suggested for high quality optical use are the borogermanosilicate glasses represented in FIG. 1. FIG. 1 is a ternary compositional diagram representing glasses containing different proportions of SiO2, GeO2 B2 O3. This diagram shows exemplary lines of constant index of refraction at 0.589μ 11 (solid lines) and exemplary lines of constant coefficient of thermal expansion 12 (dashed lines) for annealed glasses in this system. When of suitably high purity and homogeneity, glasses in this system can be used for optical transmission lines (optical waveguides) such as shown in FIG. 2. Such transmission lines incorporate a higher index of refraction glass core 21 and a lower index of refraction glass cladding 22. The index difference required to obtain adequate guidance at any wavelength depends on the dimensions of the device and is commonly expressed in terms of the numerical aperture of the device. However, it is difficult to achieve guidance if the index difference is less than one half percent. Thus, the inclusion of at least approximately 8 mole percent GeO2 in a germanosilicate glass is needed if the other glass is a borosilicate glass.
In addition to index of refraction considerations, it is desirable to use glasses possessing coefficients of expansion which differ by less than 20 percent, in order to achieve low residual stress in the fabricated device. The use of glasses which differ in coefficient of expansion by less than 5 percent is preferable in this respect.
When made by the plasma fusion process discussed below it was found that the germanosilicate glasses possessed significantly fewer bubbles (essentially none in most cases) than the borosilicate glasses. It was particularly surprising that the inclusion of as little as 0.1 mole percent of GeO2 in a borosilicate glass produced a significant reduction in bubble formation. Thus, the inclusion of from 0.1 to 5 mole percent GeO2 in an otherwise pure borosilicate glass is recommended for bubble content reduction while holding the variation of refraction to within 10 percent of the total variation over the contemplated borogermanosilicate composition range. In an examplary boule, a 1 mole percent GeO2 glass was of pristine clarity while a neighboring borosilicate composition (approximately 15 mole percent B2 O3) contained noticeable bubbles. The following pair of approximate glass compositions is recommended for optical transmission line use: (1) 85 mole percent SiO2, 15 mole percent GeO2 -- core; (2) 85 mole percent SiO2, mole percent B2 O3, 2.5 mole percent GeO2 -- cladding. Glasses of approximately these compositions can be used within the tolerance ranges desired by the device designer. Other composition pairs can be found by referring to FIG. 1, while considering index of refraction and coefficient of thermal expansion. The composition field shown in FIG. 1 (i.e., at least 75 mole percent SiO2) is a preferred range. However, the production of glasses with at least 50 mole percent SiO2 and less than approximately 40 mole percent GeO2, B2 O3 or other high volatility oxide benefits from the teaching of this disclosure.
Powder Production
Powders suitable for use in the production, by plasma fusion, of the above-described optical glasses have been produced by several methods. The following methods have proven most suitable when used in conjunction with the investigated glass system. However, other equivalent methods may find use in the production of other compositions. In one method a quantity of finely divided silica powder (for example, a powder with average partical size approximately 75 Angstroms) is combined with a solution containing constituents which, when in oxide form, constitute the other glass-forming materials. For example, an aqueous solution of ammonium pentaborate ((NH4)2 B10 O16 .sup.. 8H2 O) can be used when the production of a borosilicate glass is contemplated. The slurry is liquid dried by spraying into a quantity of flowing ammoniated acetone. The slurry is filtered and the filtered particles dried to produce the precursor material, which will subsequently be processed into the powders ultimately to be used to produce the optical glass boule.
In an alternate procedure all of the glass-forming materials are incorporated in solution and the mixed solution hydrolyzed by spraying into a quantity of ammoniated water. For example, tetramethoxy silane, Si(OCH3)4, trimethoxy borine, B(OCH3)3, and tetraethoxy germanium, Ge(OC2 H5)4, can be used when the production of borogermanosilicate glass is contemplated. Any one of a number of other organometallic or inorganic compounds may be used in this procedure (e.g., tetraethoxy silane, silicon tetrachloride, germanium tetrachloride and boric acid). Care must be taken, however, to consider the degree of solubility of any of these compounds in the liquid into which the mixture of compounds is sprayed. If one of the compounds has some degree os solubility in this liquid, a portion of that compound will be carried off during the filtering step and the original proportions must be adjusted to achieve the desired composition in the product powers. If the use of soluble compounds is indicated by economic or other reasons, an alternate procedure is the production of a gel which can be dried without filtering. Such a dried gel produces a light friable material which can easily be reduced to the desired particle size.
The damp powders produced by the filtering of the above produced slurries can be dried, for example, by placing them in an oven to bake in air or vacuum or other appropriate atmosphere at some elevated temperature. Exemplary powders have been dried in air or vacuum at approximately 110° C for times of more than 16 hours. This drying step produces a friable cake which can be gently crushed and screened to the desired particle size. Screening through a 20 mesh nylon screen has proved advantageous. The particle matter thus produced is the precursor material for subsequent processing to the desired glassy powder.
The most desirable product for use in the ultimate plasma torch production of a glass boule would be bubble free, compositionally uniform and uniformly sized particles of the desired glass composition. It is the goal of the hereunder described powder preparation steps to approach as near as possible to this ideal. The basic requirement is a heat treatment which reduces the compounds used, to oxide form and combines the oxides to produce a glassy or at least partially glassy material. A two-step heat treatment has been found to be advantageous in this regard. The first step, some 200° to 400° centrigrade below the temperature of the subsequent step, serves to promote oxide formation and drive off volatile constituents leaving the glass forming materials primarily in oxide form. The second step, at a temperature between 750° C and 950° C for silicate glasses, serves to combine the oxides to particles as near as possible to the ideal described above. The second step heat treatment temperature is chosen to be as high as possible to maximize glass formation and compositional uniformity but not high enouth to produce an inordinate amount of agglomeration of the particles. This latter consideration is particularly important when the highest degrees of production purity are required. If the heat treatment temperature is not too high, the product remains particulate or forms a light friable cake which is easily crushed without vigorous grinding or other pulverizing steps which would provide an avenue for the introduction of impurities.
For the best results in the plasma fusion steps it has been found to be desirable to use particles between a maximum and a minimum particle size. It has been found that particles which are too large to pass through approximately a 20 mesh screen are not sufficiently melted and fined during their course through the plasma flame. Particles which will pass through a 100 mesh screen exhibit an inordinate amount of loss through vaporization during their course through the plasma flame. Thus it has been found desirable to screen the heat treated powders through a 20 mesh screen onto a 100 mesh screen in order to produce powders for use in the plasma fusion step.
Plasma Fusion
FIG. 3 shows an exemplary apparatus for the production of a boule of optical glass by the fusion of a powder in a plasma flame. In this apparatus a high-powered r-f generator 31 (of the order of 10 100 kilowatts) excites the coil 32 of a plasma torch 33. In this exemplary apparatus, the plasma torch consists of a fused silica mantle 34 connected by a tube 35 to a source of gas 36. The gas source 36 feeds the gas desired for the plasma discharge 37 into the mantle 34. The plasma discharge 37 produces an incadescent flame whose temperature can reach of the order of 20,000° C at its center. Plasma torches are described in the literature (e.g., International Science and Technology, June 1962, page 42).
The powders to be fused are directed into the flame 37 by a tube 38 from a powder source 39. In an exemplary apparatus the powder source 39 consisted of a vibratory powder feeder which continuously introduced a regulated quantity of powder into a stream of helium gas flowing at a rate of approximately 140 liters per hour. The power feed rate was adjusted somewhat after visual observation of the forming boule, starting at a rate of 200 grams per hour.
The powder-gas stream from the powder source 39 is directed against the center of the molten portion 43 of the forming boule 40. Boule formation is initiated by directing the powder-gas stream against a bait 41. The bait 41 is supported on a pedestal 42, which is rotated in order to promote the symmetry of the boule 40. The pedestal is lowered at a rate sufficient to keep the position of the molten 43 portion of the boule 40 constant relative to the flame 37 and feed tube 38.
EXAMPLES Example 1
A powder containing 84.5 mole percent SiO2 and 15.5 mole percent B2 O3 was produced by stirring together 3.2 liters of triply distilled water, 186.7 grams of (NH4)2 B10 O16.sup.. 8H2 O and 309 grams of an amorphous silica powder having an average particle size of less than 100 A. The mixture was stirred for 2 hours at 60° C to produce a slurry. The slurry was sprayed into a stirred bath approximately 10 times its volume of a 25-to-1 by volume mixture of acetone and NH4 OH solution. The NH4 OH solution was 28 weight percent NH4 OH in water. The resulting particles were filtered from the solution and dried at 110° C for at least 16 hours. The drying time and temperature are not critical.
The dried powder formed a friable cake, which was placed in a plastic bag and crushed. The resulting powder was passed through a 20 mesh nylon screen. The screened powders were placed in a fused silica dish and raising the temperature of the powder from room temperature at a rate of 200° centigrade per hour in a furnace while the powder was exposed to air and heat treated at 600° C for 2 hours then at 750° C for 2 hours, cooled to 500° C in the furnace and removed to room temperature. The heat treated powder was a friable cake which was crushed gently in a plastic bag and screened through a 20 mesh nylon screen onto a 100 mesh nylon screen. The powder which did not pass through the 100 mesh screen was used to produce bulk glass by plasma fusion.
For fusion the powder was placed in a vibratory powder feeder, which fed the powder at a rate of approximately 200 grams per hour into a stream of helium gas flowing at approximately 140 liters per hour into a 3 mm inner diameter tube. The gas-powder mixture was directed into the plasma flame against the fused surface of the forming boule through a fused silica injection probe withh a 3 mm inner diameter. Boule growth was initiated by directing the powders at the surface of a fused silica bait consisting of a 3.8 cm diameter plate, 0.3 cm thick. The bait and forming boule were rotated at 100 revolutions per minute and lowered at a rate sufficient to keep the molten surface of the forming boule at a constant position relative to the flame and the injection probe.
A boule of optical glass (containing few bubbles) approximately 5 cm in diameter and 5 cm long was produced. The composition of the glass was 84.5 mole percent SiO2 and 15.5 mole percent B2 O3.
Example 2)
A powder containing 85.6 mole percent SiO2, 4.9 mole percent GeO2 and 9.5 mole percent B2 O3 was produced by stirring together, at room temperature, 486 ml of tetramethoxysilane, Si(OCH3)4, 89.7 ml of trimethoxy borine, B(OCH3)3, and 44.2 ml of tetraethoxy germanium, Ge(OC2 H5)4. The solution was injected through a 0.01 mm diameter orifice into a swirling bath of 10 times its volume of an ammoniated water solution. The ammoniated water solution was made by mixing water and a 28 weight percent NH3 OH aqueous solution in a 25:1 ratio by volume. The resulting particles were filtered and dried at 110° C for at least 16 hours. The drying time and temperature are not critical. The resulting material was processed to a powder between 20 mesh and 100 mesh size as in Example 1, except for the fact that the high temperature heat treatment took place for four hours at 925° C.
The resulting powder was fused into a boule of optical glass by a plasma fusion process essentially similar to Example 1. The composition of the glass was 87.5 mole percent SiO2, 4.3 mole percent GeO2 and 8.2 mole percent B2 O3. This glass was essentially bubble free. Through the growth of several compositions it was determined that as little as 0.1 mole percent GeO2 in a borosilicate glass was sufficient to greatly reduce or essentially eliminate bubble formation in these glasses.
The plasma flame was produced by a 35 kilowatt RF generator, exciting O2 flowing at approximately 900 liters per hour in a 30 cm inner diameter plasma torch.

Claims (7)

What is claimed is:
1. Method of producing an essentially bubble-free glass boule, suitable for use as a low loss optical waveguide material, and of good composition control in mixed oxide glass systems which include relatively volatile minor constituents, comprising
1. introducing a quantity of homogeneous prereacted particulate matter into a gas stream, said matter being of such particle size as to pass through a 20 mesh screen but not through a 100 mesh screen
2. directing the gas-particle stream into a plasma discharge against a bait, thereby fusing the particulate matter to form said glass boule wherein the particulate matter has been produced by
a. producing an intimate mixture of glass forming materials, which materials comprise at least 50 mole percent of a major constituent and at least 5 mole percent and less than about 40 mole percent of at least one minor constituent, at least one of which minor constituents, when in oxide form, possesses a vapor pressure at least 1.5 times as great as the vapor pressure of the major constituent, when in oxide form, at the temperature necessary to fuse the particulate matter to form the glass body;
b. producing a particulate precursor material from the intimate mixture;
c. heat treating the particular precursor material to produce an at least partially glassy product, and
d. screening the heat treated material and selecting a cut of powder passing through a 20 mesh screen but not passing through a 100 mesh screen.
2. Method of claim 1 in which the major constituent, when in oxide form, is SiO2.
3. Method of claim 2 in which the at least one minor constituent, when in oxide form, includes from 5 mole percent to 40 mole percent B2 O3, and from 0.1 mole percent to 5 mole percent GeO2 based on the composition of the particulate matter.
4. Method of claim 2 in which the at least one minor constituent, when in oxide form, includes from 8 mole percent to 40 mole percent GeO2, based on the composition of the particulate matter.
5. Method of claim 2 in which the intimate mixture, and, subsequently the particulate precursor material are produced by a method including mixing particulate SiO2 with a liquid including the at least one minor constituent to form a slurry; injecting the slurry into a liquid different from the solvent of the solution so as to produce a precipitate; and drying the precipitate.
6. Method of claim 1 in which the intimate mixture and, subsequently, the particulate precursor material is produced by a method including mixing together source liquids including the major constituent and the at least one minor constituent; injecting the mixed source liquids into a precipitator liquid so as to produce a precipitate; and drying the precipitate.
7. A boule of glass produced by the method of claim 1.
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Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2351069A1 (en) * 1976-05-10 1977-12-09 Pittsburgh Corning Corp PULVERULENT COMPOSITION OF BOROSILICATE FOR USE IN THE PREPARATION OF CELLULAR BOROSILICATE BODIES
FR2410291A1 (en) * 1977-11-25 1979-06-22 Cselt Centro Studi Lab Telecom METHOD AND APPARATUS FOR THE CONTINUOUS PRODUCTION OF OPTICAL FIBERS
DE3000762A1 (en) * 1979-01-10 1980-07-24 Quartz & Silice METHOD FOR PRODUCING A PREFORM FOR AN OPTICAL WAVE GUIDE
FR2521123A1 (en) * 1982-02-09 1983-08-12 Thomson Csf PROCESS FOR PRODUCING DOPED SILICA GLASS FOR OPTICAL FIBER PREFORM PREPARATION
GB2134896A (en) * 1983-02-10 1984-08-22 Int Standard Electric Corp Optical waveguide preform fabrication
US4477580A (en) * 1982-09-28 1984-10-16 At&T Bell Laboratories Method for making germanium-silicate gel glass and articles
EP0173183A1 (en) * 1984-08-18 1986-03-05 Mitsubishi Materials Corporation Radiation-resistant optical conductor
US4707174A (en) * 1983-12-22 1987-11-17 American Telephone And Telegraph Company, At&T Bell Laboratories Fabrication of high-silica glass article
EP0271281A2 (en) * 1986-12-11 1988-06-15 AT&T Corp. Method for fabricating articles which include high silica glass bodies and articles formed thereby
US4767429A (en) * 1986-12-11 1988-08-30 American Telephone & Telegraph Co., At&T Bell Laboratories Glass body formed from a vapor-derived gel and process for producing same
US4812153A (en) * 1987-01-12 1989-03-14 American Telephone And Telegraph Company Method of making a glass body having a graded refractive index profile
EP0578553A1 (en) * 1992-07-07 1994-01-12 Alcatel N.V. Process of making a silica powder and use of such a powder in the manufacture of optical fibre preforms
US5279633A (en) * 1988-09-21 1994-01-18 American Telephone & Telegraph Method of producing a glass body
AU657845B2 (en) * 1992-03-17 1995-03-23 Sumitomo Electric Industries, Ltd. Method and apparatus for producing glass thin film
EP0838439A1 (en) * 1996-10-24 1998-04-29 Alcatel Process for manufacturing a preform for optical fibres
US5888587A (en) * 1992-07-07 1999-03-30 Alcatel N.V. Method of manufacturing silica powder and use of such powder in making an optical fiber preform
US6071487A (en) * 1997-07-17 2000-06-06 Alcatel Method of manufacturing a silica powder
US20040089026A1 (en) * 2001-11-30 2004-05-13 Bellman Robert A. Precursor and method of growing doped glass films
US20050054510A1 (en) * 2001-04-06 2005-03-10 Ellison Adam J. Dispersal of optically active ions in glass
US20110100061A1 (en) * 2009-10-30 2011-05-05 James Fleming Formation of microstructured fiber preforms using porous glass deposition
US20120301610A1 (en) * 2010-04-26 2012-11-29 Furukawa Electric Co., Ltd. Method of producing glass preform and apparatus for producing the same
US20140127464A1 (en) * 2011-07-05 2014-05-08 Angela Eberhardt Method For Producing A Conversion Element, And Conversion Element
US9630162B1 (en) * 2007-10-09 2017-04-25 University Of Louisville Research Foundation, Inc. Reactor and method for production of nanostructures
US10427970B1 (en) * 2016-10-03 2019-10-01 Owens-Brockway Glass Container Inc. Glass coatings and methods to deposit same

Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2809124A (en) * 1954-08-26 1957-10-08 Du Pont Production of inorganic oxide composition coatings
US3177057A (en) * 1961-08-02 1965-04-06 Engelhard Ind Inc Method of forming quartz fibers from extruded rods
US3255120A (en) * 1961-01-05 1966-06-07 Saint Gobain Heat and infra-red responsive glass composition and method of making it
US3275408A (en) * 1963-01-29 1966-09-27 Thermal Syndicate Ltd Methods for the production of vitreous silica
US3457102A (en) * 1964-03-27 1969-07-22 Westinghouse Electric Corp Method of coating with glass
US3458552A (en) * 1963-12-23 1969-07-29 Dynamit Nobel Ag Process for the preparation of condensed mixed metal alcoholates
US3489579A (en) * 1966-05-25 1970-01-13 Us Army Ablative heat shielding and injection cooling by addition of surface active agents
US3597252A (en) * 1966-05-07 1971-08-03 Jenaer Glaswerk Schott & Gen Method for producing glass compositions
US3640093A (en) * 1969-03-10 1972-02-08 Owens Illinois Inc Process of converting metalorganic compounds and high purity products obtained therefrom
US3645779A (en) * 1968-07-11 1972-02-29 Leybold Heraeurs Verwaltung Gm Method of coating a transparent synthetic polymer substrate with glass boron oxide-silicon dioxide
US3669693A (en) * 1968-06-24 1972-06-13 Corning Glass Works Germania-silica glasses and method of coating
US3690905A (en) * 1970-05-22 1972-09-12 Leitz Ernst Gmbh Optical glass having anomalous partial dispersion
US3759683A (en) * 1969-08-13 1973-09-18 Jenaer Glaswerk Schott & Gen Process for the manufacture of multi component substances
US3762936A (en) * 1967-07-31 1973-10-02 Du Pont Manufacture of borosilicate glass powder essentially free of alkali and alkaline earth metals
US3801294A (en) * 1971-12-15 1974-04-02 Corning Glass Works Method of producing glass
US3884550A (en) * 1973-01-04 1975-05-20 Corning Glass Works Germania containing optical waveguide

Patent Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2809124A (en) * 1954-08-26 1957-10-08 Du Pont Production of inorganic oxide composition coatings
US3255120A (en) * 1961-01-05 1966-06-07 Saint Gobain Heat and infra-red responsive glass composition and method of making it
US3177057A (en) * 1961-08-02 1965-04-06 Engelhard Ind Inc Method of forming quartz fibers from extruded rods
US3275408A (en) * 1963-01-29 1966-09-27 Thermal Syndicate Ltd Methods for the production of vitreous silica
US3458552A (en) * 1963-12-23 1969-07-29 Dynamit Nobel Ag Process for the preparation of condensed mixed metal alcoholates
US3457102A (en) * 1964-03-27 1969-07-22 Westinghouse Electric Corp Method of coating with glass
US3597252A (en) * 1966-05-07 1971-08-03 Jenaer Glaswerk Schott & Gen Method for producing glass compositions
US3489579A (en) * 1966-05-25 1970-01-13 Us Army Ablative heat shielding and injection cooling by addition of surface active agents
US3762936A (en) * 1967-07-31 1973-10-02 Du Pont Manufacture of borosilicate glass powder essentially free of alkali and alkaline earth metals
US3669693A (en) * 1968-06-24 1972-06-13 Corning Glass Works Germania-silica glasses and method of coating
US3645779A (en) * 1968-07-11 1972-02-29 Leybold Heraeurs Verwaltung Gm Method of coating a transparent synthetic polymer substrate with glass boron oxide-silicon dioxide
US3640093A (en) * 1969-03-10 1972-02-08 Owens Illinois Inc Process of converting metalorganic compounds and high purity products obtained therefrom
US3759683A (en) * 1969-08-13 1973-09-18 Jenaer Glaswerk Schott & Gen Process for the manufacture of multi component substances
US3690905A (en) * 1970-05-22 1972-09-12 Leitz Ernst Gmbh Optical glass having anomalous partial dispersion
US3801294A (en) * 1971-12-15 1974-04-02 Corning Glass Works Method of producing glass
US3884550A (en) * 1973-01-04 1975-05-20 Corning Glass Works Germania containing optical waveguide

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Nassaugki et al. "Low Loss Fused Silica made by the Plasus Torch" Applied Optics 13(4) Apr. 1974 pp. 744-745. *

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2351069A1 (en) * 1976-05-10 1977-12-09 Pittsburgh Corning Corp PULVERULENT COMPOSITION OF BOROSILICATE FOR USE IN THE PREPARATION OF CELLULAR BOROSILICATE BODIES
US4075025A (en) * 1976-05-10 1978-02-21 Pittsburgh Corning Corporation Method of forming a potassium aluminoborosilicate frit
FR2410291A1 (en) * 1977-11-25 1979-06-22 Cselt Centro Studi Lab Telecom METHOD AND APPARATUS FOR THE CONTINUOUS PRODUCTION OF OPTICAL FIBERS
DE3000762A1 (en) * 1979-01-10 1980-07-24 Quartz & Silice METHOD FOR PRODUCING A PREFORM FOR AN OPTICAL WAVE GUIDE
US4265649A (en) * 1979-01-10 1981-05-05 Saint-Gobain Industries Method for preparing a preform for optical waveguides
FR2521123A1 (en) * 1982-02-09 1983-08-12 Thomson Csf PROCESS FOR PRODUCING DOPED SILICA GLASS FOR OPTICAL FIBER PREFORM PREPARATION
EP0086132A1 (en) * 1982-02-09 1983-08-17 Thomson-Csf Method of making doped silica glass for processing a preform for an optical fibre
US4493720A (en) * 1982-02-09 1985-01-15 Thomson-Csf Process for producing doped vitreous silica for preparing a preform for an optical fibre
US4477580A (en) * 1982-09-28 1984-10-16 At&T Bell Laboratories Method for making germanium-silicate gel glass and articles
GB2134896A (en) * 1983-02-10 1984-08-22 Int Standard Electric Corp Optical waveguide preform fabrication
US4707174A (en) * 1983-12-22 1987-11-17 American Telephone And Telegraph Company, At&T Bell Laboratories Fabrication of high-silica glass article
EP0173183A1 (en) * 1984-08-18 1986-03-05 Mitsubishi Materials Corporation Radiation-resistant optical conductor
EP0271281A3 (en) * 1986-12-11 1990-01-17 American Telephone And Telegraph Company Method for fabricating articles which include high silica glass bodies and articles formed thereby
JPS63215525A (en) * 1986-12-11 1988-09-08 エイ・ティ・アンド・ティ・コーポレーション Manufacture of product containing high silica glass body
EP0271281A2 (en) * 1986-12-11 1988-06-15 AT&T Corp. Method for fabricating articles which include high silica glass bodies and articles formed thereby
US4767429A (en) * 1986-12-11 1988-08-30 American Telephone & Telegraph Co., At&T Bell Laboratories Glass body formed from a vapor-derived gel and process for producing same
US4812153A (en) * 1987-01-12 1989-03-14 American Telephone And Telegraph Company Method of making a glass body having a graded refractive index profile
US5279633A (en) * 1988-09-21 1994-01-18 American Telephone & Telegraph Method of producing a glass body
AU657845B2 (en) * 1992-03-17 1995-03-23 Sumitomo Electric Industries, Ltd. Method and apparatus for producing glass thin film
US5503650A (en) * 1992-03-17 1996-04-02 Sumitomo Electric Industries, Ltd. Method for producing a glass thin film with controlloing an oxide vapor of an additive
US5660611A (en) * 1992-03-17 1997-08-26 Sumitomo Electric Industries, Ltd. Method for producing glass thin film
US5888587A (en) * 1992-07-07 1999-03-30 Alcatel N.V. Method of manufacturing silica powder and use of such powder in making an optical fiber preform
EP0578553A1 (en) * 1992-07-07 1994-01-12 Alcatel N.V. Process of making a silica powder and use of such a powder in the manufacture of optical fibre preforms
FR2693451A1 (en) * 1992-07-07 1994-01-14 Alcatel Nv A method of manufacturing a silica powder and applying such a powder to the production of a preform for optical fiber.
US6047568A (en) * 1992-07-07 2000-04-11 Alcatel N.V. Method of manufacturing a silica powder and use of such a powder in making an optical fiber preform
EP0838439A1 (en) * 1996-10-24 1998-04-29 Alcatel Process for manufacturing a preform for optical fibres
FR2755124A1 (en) * 1996-10-24 1998-04-30 Alsthom Cge Alcatel METHOD FOR MANUFACTURING AN OPTICAL FIBER PREFORM
US6071487A (en) * 1997-07-17 2000-06-06 Alcatel Method of manufacturing a silica powder
US20050054510A1 (en) * 2001-04-06 2005-03-10 Ellison Adam J. Dispersal of optically active ions in glass
US20040089026A1 (en) * 2001-11-30 2004-05-13 Bellman Robert A. Precursor and method of growing doped glass films
US9630162B1 (en) * 2007-10-09 2017-04-25 University Of Louisville Research Foundation, Inc. Reactor and method for production of nanostructures
US20110100061A1 (en) * 2009-10-30 2011-05-05 James Fleming Formation of microstructured fiber preforms using porous glass deposition
US20120301610A1 (en) * 2010-04-26 2012-11-29 Furukawa Electric Co., Ltd. Method of producing glass preform and apparatus for producing the same
US20140127464A1 (en) * 2011-07-05 2014-05-08 Angela Eberhardt Method For Producing A Conversion Element, And Conversion Element
US10427970B1 (en) * 2016-10-03 2019-10-01 Owens-Brockway Glass Container Inc. Glass coatings and methods to deposit same

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